An Introduction to Ecology & the Biosphere

1. An Introduction to Ecology&the Biosphere Campbell & reece Chapter 52

2. Ecology from Greek, oikos = home scientific study of interactions between organisms & environment

4. Scope of Ecological Research Organismal Ecology: concerned with individual’s structure, physiology, behavior & its challenges posed by its environment Population Ecology:analyzes factors that affect population size; how & why it changes over time Community Ecology: interactions between species: how predation, competition affect community structure Ecosystem Ecology: nrg flow & biochemical cycling between organisms & their environment; abiotic factors included Landscape Ecology: factors controlling exchanges of nrg, materials & organisms across multiple rcosystems Global Ecology: how regional exchange of nrg & materials influences functioning & distribution of organisms across the biosphere

5. Climate long-term, prevailing weather conditions in given area *most significant influence on the distribution of organisms on land & in oceans

6. 4 Components of Climate Temperature Precipitation Sunlight Wind

7. Global Climate Patterns • determined mostly by • input of solar nrg • establishes temp variations • cycles of air & water movement • evaporation of water  dramatic latitudinal variations in climate • Earth’s movement in space

8. Latitudinal Variation in Sunlight Intensity Earth’s curved shape causes latitudinal variation in intensity of sunlight. because sunlight hits Tropics (23.5° N and 23.5° S latitude) most directly, more heat & light /unit surface area are delivered there @ higher latitudes sunlight strikes Earth @ oblique angle so light nrg more diffuse on Earth’s surface

9. Global Air Circulation & Precipitation Patterns intense solar radiation @ equator initiates global pattern of air circulation & precipitation hi temps evaporate water  warm, wet air rises  flow toward the poles air cools  precipitation  dry air masses descend @ ~ 30° latitude (N & S) @~60° latitudes air rises  cool  precipitation  to poles

10. Global Air Currents

11. Wind Patterns air flowing close to surface creates predictable global wind patterns as Earth rotates land near equator moves faster than that @ poles, deflecting the winds from staying on vertical path cooling trade winds blow east  west in the tropics prevailing westerlies blow from west  east in temperate zones

12. Global Wind Patterns

13. Climate • Macroclimate: patterns on the global, regional, & landscape level • Microclimate: very fine localized patterns • Climate patterns can be modified by: • seasonal variations in climate • large bodies of water • mountain ranges

14. Seasonality Earth’s tilted axis of rotation & revolution around Sun every year cause strong seasonal cycles in mid to hi latitudes

15. Bodies of Water because of hi specific heat of water, oceans & large lakes tend to moderate the climate of nearby land hot day: land warmer than water  air over land warms & rises  draws cooler air from over water to land @ night: land cools faster than water  air over now warmer water rises  draws cooler air over land back over water

16. Lake-Effect Snow

17. Global Circulation of Surface Water

18. Mountains

19. Microclimate • every environment on Earth is characterizes by small-scale differences in abiotic factors • chemical & physical attributes: • temperature, amt of shade, light, water & nutrients, fallen tree used as shelter

20. Global Climate Change • increasing greenhouse gas concentrations in the air are warming Earth & altering the distributions of many species • some will thrive • others will not be able to shift their ranges quickly enough to reach suitable habitat

23. Biomes major life zones characterized by vegetation type (in terrestrial biomes) or by the physical environment (in aquatic biomes)

24. Climograph plot of annual mean temperature & precipitation in a particular region

25. Climograph for Some Major Biomes

26. Climographs show that temp & precipitation are correlated with biomes because other factors also play a role in biome location: biomes can overlap

27. General Features of Terrestrial Biomes most named for major physical or climatic features & for their predominant vegetation each biome also characterized by: microorganisms fungi animals all adapted to that particular environment

28. Ecotone area of integration: where biomes overlap

29. Terrestrial Biomes • layering w/in biome due to shapes & sizes of plants • flora dependent on annual precipitation & temps

30. Biome Species Composition • varies w/in each biome • ex: eastern part of one large lake may have different water bird than western portion

31. Disturbance • event that changes a community: removes organisms from it & alters the resource availability • ex: forest fire

32. Tropical Forest • Distribution: equatorial & subequatorial • Precipitation: • Tropical Rainforest: constant, 200 -400 cm/yr • Tropical Dry Forest: seasonal, 150 – 200 cm/yr • Temperature: • high all yr, average 25 – 29°C , little seasonal variation

33. Tropical Forest

34. Tropical Forest: Plants vertically layered intense competition for light

35. Tropical Forest Plants • Tropical Rainforest • see all layers, some with 2 layers of subcanopy trees • broadleaf evergreen trees dominate • epiphytes (air plants) & orchids typically cover trees • Tropical Dry Forest • see fewer layers • drop leaves during dry season • commonly have thorny shrubs & succulent plants

36. Tropical Forest: Animals millions of species 5 – 30 million undiscovered species of insects, spiders, other arthropods highest animal diversity than anywhere else on Earth all adapted to vertically layered environment

37. Tropical Forest: Human Impact thriving communities of man have lived in tropical forests for hundreds of years overpopulation leading to agriculture & development are destroying many tropical forests

38. DESERT • Distribution: • occur in bands near 30° N & S latitude or in interior of continents • Precipitation: • low & variable; <30 cm/yr • Temperature : • variable seasonally & daily • hot desert: max T may > 50°C • dry desert: low T may < -30°C

39. World Distribution of Deserts

40. Deserts

41. Desert Plants • see low, widely scattered vegetation • see more bare ground than other terrestrial biomes • succulents • cacti • euphorbs • deeply rooted shrubs & herbs • grow during brief rainy periods

42. Desert Plants • Adaptations: • heat & desiccation tolerance • water storage • reduced leaf surface area • CAM photosynthesis • physical defenses: • spines • chemical defenses: • toxins in leaves of shrubs

43. Desert Animals Common animals: Snakes Lizards Scorpions Ants Beetles Birds: migratory & resident seed-eating Rodents

44. Desert Animal Adaptations • many species are nocturnal • water conserved in variety of ways: • only water some get is by metabolizing carbohydrates  water + carbon dioxide

45. Desert: Human Impact use of long distance transport of water & deep groundwater wells have allowed large populations of man to make the desert their home end result  decreased diversity of some deserts

46. SAVANNA • Distribution: • equatorial & subequatorial • Precipitation: • seasonal rainfall 30 – 50 cm/yr • dry season can last 8 – 9 months • Temperature : • warm year-round: 24 – 29 °C • more seasonal variation than tropical forests

47. Savanna Distribution

48. Savanna

49. Savanna Plants scattered, variable density of trees most plants have small leaves (adaptation to dry conditions) Fires common in dry season: most dominant plant species are fire-adapted & drought-tolerant grasses & forbes (clover, wildflowers) tolerant of large grazing herbivores

50. Savanna Animals • dominant herbivores are insects • especially termites • large herbivores migrate toward thicker vegetation & watering holes during dry season